Corticosteroids (or glucocorticoids) having anti-inflammatory properties are widely used for the treatment of inflammatory conditions or disorders of skin, airways, eye, GI tract, joints, CNS etc., and several autoimmune disorders. Some of the inflammatory skin disorders where treatment with glucocorticoids is prescribed are eczema, psoriasis, allergic dermatitis, pruritis, hypersensitivity reactions etc. Inflammatory or allergic conditions of the airways for which glucocorticoids are used include disorders of nose, throat or lungs such as rhinitis (including hay fever), nasal polyps, asthma (including allergen-induced asthmatic reaction), chronic obstructive pulmonary disease, interstitial lung disease, fibrosis, etc. Glucocorticoid administration is also used for inflammatory bowel disorders such as ulcerative colitis and Crohn's diseases; and inflammatory joint disorders such as rheumatoid arthritis which are autoimmune diseases.
However, administration of corticosteroids in general may cause, in addition to the desired pharmacological effect, undesirable or adverse side effects at sites distant from the target tissue, the so-called systemic effects. Some of the undesired systemic effects encountered include widespread immunosuppression, increased bone turnover, impaired growth, skin thinning, diabetes, obesity, water retention, and progesterone and estrogen related disorders. It is therefore desirable to have glucocorticoids that possess potent anti-inflammatory activity at the target tissue, with minimal or no systemic activity at therapeutic doses when used for chronic treatment.
Classical glucocorticoids are described in U.S. Pat. No. 4,335,121 (e.g., (S)-fluoromethyl 6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-propionyloxy-3-oxoandrosta-1,4-diene-17β-carbothioate (Fluticasone)); U.S. Pat. No. 3,007,923 (e.g., 16α-methyl-9α-fluoro-1,4-pregnadiene-11β,17α,21-triol-3,20-dione (Dexamethasone)); U.S. Pat. No. 3,929,768 (e.g., (11β,16α)-16,17-[Butylidenebis(oxy)]-11,21-dihydroxypregna-1,4-diene-3,20-dione (Budesonide)); and U.S. Pat. No. 4,472,393 (e.g., (11β,16α)-9,21-Dichloro-17-[(2-furanylcarbonyl)oxy]-11-hydroxy-16-methylpregna-1,4-diene-3,20-dione (Mometasone furoate)). These drugs are potent glucocorticoids that are already in clinical use. However, at high multiples of efficacy dose these drugs have the potential to cause adverse systemic side effects.
PCT publication WO 99/01467 describes therapeutically active steroidal compounds or salts or solvates having lactone group connected to the cyclopentane ring of the steroid nucleus (as given below).
These compounds have been described to have reduced potential for systemic activity due to the relative instability of the lactone system in plasma. The compounds of the present invention do not possess a lactone group connected to the cyclopentane ring.